FREQUENCY AND TEMPERATURE DEPENDENCES OF H-1-NMR T1 IN PURE AND DOPED POLYACETYLENE

Abstract Spin-lattice relaxation rates 1/T1 of 1H nuclei were measured in pure and Br2-doped trans-polyacetylene. At room temperature the frequency dependence obeyed 1/2 power law both in pure and doped. The temperature variation depended on samples in pure case. For first group samples the data points fitted a T1 vs T−1/4 law between 1.3 and 295 K at 9.0 MHz. At higher frequencies they deviated at low temperatures. For second group the temperature dependence was a little steeper. The T−1/4 law was explained by the phonon scattering of one-dimensionally moving electron spins (neutral solitons). In Br2-doped one a T1T=const. law fitted between 4.2 and 295 K.